LoongArch: Use UNSPEC for fmin/fmax RTL pattern [PR105414]
Commit Message
I made a mistake defining fmin/fmax RTL patterns in r13-2085: I used
smin and smax in the definition mistakenly. This causes the optimizer
to perform constant folding as if fmin/fmax was "really" smin/smax
operations even with -fsignaling-nans. Then pr105414.c fails.
We don't have fmin/fmax RTL codes for now (PR107013) so we can only use
an UNSPEC for fmin and fmax patterns.
gcc/ChangeLog:
PR tree-optimization/105414
* config/loongarch/loongarch.md (UNSPEC_FMAX): New unspec.
(UNSPEC_FMIN): Likewise.
(fmax<mode>3): Use UNSPEC_FMAX instead of smax.
(fmin<mode>3): Use UNSPEC_FMIN instead of smin.
---
gcc/config/loongarch/loongarch.md | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
Comments
I have no problem.
Thanks.
在 2022/9/24 下午8:47, Xi Ruoyao 写道:
> I made a mistake defining fmin/fmax RTL patterns in r13-2085: I used
> smin and smax in the definition mistakenly. This causes the optimizer
> to perform constant folding as if fmin/fmax was "really" smin/smax
> operations even with -fsignaling-nans. Then pr105414.c fails.
>
> We don't have fmin/fmax RTL codes for now (PR107013) so we can only use
> an UNSPEC for fmin and fmax patterns.
>
> gcc/ChangeLog:
>
> PR tree-optimization/105414
> * config/loongarch/loongarch.md (UNSPEC_FMAX): New unspec.
> (UNSPEC_FMIN): Likewise.
> (fmax<mode>3): Use UNSPEC_FMAX instead of smax.
> (fmin<mode>3): Use UNSPEC_FMIN instead of smin.
> ---
> gcc/config/loongarch/loongarch.md | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md
> index 3787fd8230f..214b14bddd3 100644
> --- a/gcc/config/loongarch/loongarch.md
> +++ b/gcc/config/loongarch/loongarch.md
> @@ -35,6 +35,8 @@ (define_c_enum "unspec" [
> ;; Floating point unspecs.
> UNSPEC_FRINT
> UNSPEC_FCLASS
> + UNSPEC_FMAX
> + UNSPEC_FMIN
>
> ;; Override return address for exception handling.
> UNSPEC_EH_RETURN
> @@ -1032,8 +1034,9 @@ (define_insn "smin<mode>3"
>
> (define_insn "fmax<mode>3"
> [(set (match_operand:ANYF 0 "register_operand" "=f")
> - (smax:ANYF (match_operand:ANYF 1 "register_operand" "f")
> - (match_operand:ANYF 2 "register_operand" "f")))]
> + (unspec:ANYF [(use (match_operand:ANYF 1 "register_operand" "f"))
> + (use (match_operand:ANYF 2 "register_operand" "f"))]
> + UNSPEC_FMAX))]
> ""
> "fmax.<fmt>\t%0,%1,%2"
> [(set_attr "type" "fmove")
> @@ -1041,8 +1044,9 @@ (define_insn "fmax<mode>3"
>
> (define_insn "fmin<mode>3"
> [(set (match_operand:ANYF 0 "register_operand" "=f")
> - (smin:ANYF (match_operand:ANYF 1 "register_operand" "f")
> - (match_operand:ANYF 2 "register_operand" "f")))]
> + (unspec:ANYF [(use (match_operand:ANYF 1 "register_operand" "f"))
> + (use (match_operand:ANYF 2 "register_operand" "f"))]
> + UNSPEC_FMIN))]
> ""
> "fmin.<fmt>\t%0,%1,%2"
> [(set_attr "type" "fmove")
@@ -35,6 +35,8 @@ (define_c_enum "unspec" [
;; Floating point unspecs.
UNSPEC_FRINT
UNSPEC_FCLASS
+ UNSPEC_FMAX
+ UNSPEC_FMIN
;; Override return address for exception handling.
UNSPEC_EH_RETURN
@@ -1032,8 +1034,9 @@ (define_insn "smin<mode>3"
(define_insn "fmax<mode>3"
[(set (match_operand:ANYF 0 "register_operand" "=f")
- (smax:ANYF (match_operand:ANYF 1 "register_operand" "f")
- (match_operand:ANYF 2 "register_operand" "f")))]
+ (unspec:ANYF [(use (match_operand:ANYF 1 "register_operand" "f"))
+ (use (match_operand:ANYF 2 "register_operand" "f"))]
+ UNSPEC_FMAX))]
""
"fmax.<fmt>\t%0,%1,%2"
[(set_attr "type" "fmove")
@@ -1041,8 +1044,9 @@ (define_insn "fmax<mode>3"
(define_insn "fmin<mode>3"
[(set (match_operand:ANYF 0 "register_operand" "=f")
- (smin:ANYF (match_operand:ANYF 1 "register_operand" "f")
- (match_operand:ANYF 2 "register_operand" "f")))]
+ (unspec:ANYF [(use (match_operand:ANYF 1 "register_operand" "f"))
+ (use (match_operand:ANYF 2 "register_operand" "f"))]
+ UNSPEC_FMIN))]
""
"fmin.<fmt>\t%0,%1,%2"
[(set_attr "type" "fmove")